Means for retarding rate of firing of automatic firearms



G. lRoNslDE 2,363,965

MEANS FOR RETARDING RATE OF FIRING OF AUTOMATIC FIREARMS Nov. 28, 1944.

3 Sheets-Sheet` 1 Filed March 2'?,A 1941 Nov. 28, 1944. G. lRoNslDE 2,363,965

MEANS FOR RETARDING RATE 0F FIRING OF AUTOMATIC FIREARMS lG. lRoNslDE Nov. 28, 1944.

MEANS FOR RETARD'ING RATE OF FIRING OF AUTOMATIC FVIREARMS 3 sheetssheet 5 Filed NIE-.roh 27, 1941 Dri/zg Patented Nov. 28, 1944 MEANS FOR RETARDING RATE OF FIRJNG OF AUTOMATIC FIREARMS George Ironside, Hartford, Conn., assignor to Colts Patent Fire Arms Manufacturing Company, Hartford. Conn., a corporation of Connecticut Application March 27, 1941, Serial No. 385,397

2 Claims.

My present invention relates to automatic rearms of the recoil type wherein the barrel of the rearm is supported Within the breech casing for longitudinal reciprocating movement during functioning of the firearm.

Prior to my present invention, automatic rearms of the recoil belt-fed cartridge type have been designed and constructed to accomplish the utmost in rapidity of firing of the cartridges automatically fed into the rearm during functioning thereof by the recoil and counter-recoil movements of parts within `the breech casing including the movement of the barrel extension and breech bolt. Also, certain movingr parts within the breech casing at definite intervals are locked and unlocked by automatic operation effected by the firing of the cartridges and the relative recoil and counter-recoil movements of said parts. This has been effected by means of springs, and cams similar to those shown and described in Patent No. 1,293,021 and designated by the reference characters R, N, and I. Great rapidity of ring is desirable where the automatic iirearms are mounted on aircraft. However, for ground use, under certain conditions, itis desirable to have the automatic firearm relatively slow in its action `or functioning so that the rate of firing of the cartridges is materially reduced as compared with the very lrapid firing of the firearms when used on aircraft.

In the firearm illustrated in said patent, an accelerator is provided on the lock frame just behind the breech bolt when the breech is closed, and functions, as its name implies, to give an accelerated motion to the rearward movement of the breech bolt after firing of the cartridges, thus speeding up or increasing the rapidity of the automatic functioning of the firearm.

With the foregoing in mind, the general object of my present invention may be stated to reside in the provision of means for regulating the movement of parts of the breech mechanism which control the feeding of the cartridges into the chamber or breech end of the barrel and the firing thereof after the breech has been closed, and to control and especially reduce the rate of firing of the cartridges in an automatic rearm of the type above mentioned by eliminating acceleration of the breech bolt.

More specically stated, the invention may be said to reside in the provision of means automatically operable during functioning of the gun to positively retard movement of the barrel and barrel extension into battery position subject toV movement of the breech bolt so that the barrel and barrel extension are not released for movement into battery position until the breech bolt has nearly completed its forward travel into breech-closing position.

As will become hereinafter more apparent and will be pointed out in detail, the invention provides a special construction and relative arrangement of cooperating elements to effect the re tarding of the feeding, charging, and ring mechanism of an automatic firearm whereby the rate or rapidity of ring is materially reduced as cornpared with the rate of ring under the construction and operation of said Patent No. 1,293,021 and other accelerated firearms designed especially to attain the utmost speed or rate of ring of a succession of cartridges automatically fed thereto.

In my'present application I have disclosed two mechanisms for eiecting or accomplishing the foregoing objects and which may be used jointly or separately according to the rate of ring desired, that is, the invention contemplates and includes the provision of means provided on the lock frame or similar device which limits and cushions rearward movement of the barrel extension to positively engage the barrel extension at a predetermined interval in its course of travel to prevent return of the barrel extension to battery position until said means is released by movement of the breech bolt close to breech-closing position. While this feature of the invention is amply sufficient to materially reduce the rate of ring of an automatic rearm, such as shown and described in said Patent 1,293,021, I also provide means useable in connection with the retarding mechanism, generally mentioned previously herein, to further reduce the rate of firing and consisting generally in the provision of cushioning or retarding means for the breech bolt and also preferably carried by the lock frame or similar device against which the barrel extension moves under the force created by explosion or firing of the cartridges. I, therefore, wish it to be understood that the present invention, as will become hereinafter more apparent when the details of construction and operation of the parts are eX- plained, covers constructions useable alternatively or jointly on a firearm, according to the `rate of iiring desired.

In the accompanying drawings, I have shown the now preferred embodiment of the invention, but it will be understood that the drawings are intended for illustrative purposes only and are not to be construed as dening or limiting the scope of the invention, the claims forming a part of this specication being relied upon for thatl purpose.

Inv the drawings,

Fig. 1 is a side elevation of a breech casing and feed box, and, parts mountedztherein and connected therewith, of an automatic firearm of the recoil operated type with parts broken away and partly in section showing one feature of the; f

invention; Y

Fig. 2 is a fragmentary View similar .t'oFig. -l showing the breech bolt and barrel extension oi the rearm in their rearmost recoil positions;

Fig. 3 is a view similar to Fig. -2 Ishowing the `41 barrel extension held against complete forward movement by mechanism forming a part of the present invention and just prior to release of said mechanism by counter-recoil movement of the breech bolt;

Fig. 4 is a top plan View of a barrelextension fil per 'se such as shown in Figs. V1-3,` inclusive; l

Fig. 5' isa frontend View onan enlargedrscale of thebarrel extensionshown inFig. 4;-,

.accelerated by the accelerator or levei` 0.

and located at the rear of the casing immediately behind the barrel extension. The breech bolt is adapted to be moved rearwardly, by the force created by the ring of the cartridges, from the position of Fig. 1 to the position of Fig. 2 and to be returned .from the positionshown in Fig. 2 to `the position shown in Fig. 1 by the spring 22, similar to spring 36 in said Patent No. 1,628,226

.or the spring R in Patent No. 1,293,021 located between the back plate Il and extending into the breechbolt connected therewith. i

The cooking lever 23 and extractor 24 are operated by the reciprocating movements of the breech bolt, asfdisclosed in said foregoing patents.

yAs previously mentioned, therearward move ment of thebreech bolt in Patent No. 1,293,021 is Also,

` rearward movement of the barrel extension in Fig. 6 is an enlarged sectional View taken on.

the line and lookingin the direction of the arrows :Y

E-B ofFigAy I Figj'? is `a. viewsimilar to Fig. looking'in the direction of the arrows 1 1; I y

Fig. 8 `is a fragmentary side viewpartly in elel vation and partly in section showingA a modi'i-lc'za` tion of the invention;' M y Fig. 9 lis a View similar to Fig 5 'snowingfuie modication of Figjfl Fig. l0`is a Vview'similar to Fig. v4 showingthc cushioningand retarding mechanism of Fig. J4in conjunction with additional cushioningandjre tarding mechanism for the breech bolt to further slow down the rate of firing;

Fig. .llvis a side elevation.offthemechanism., shown'in Fig. .10 'partlyin sectionand withparts broken away and illustrating the' breech bolt `Tin .its rearmcst retarded positionA in dot-and-dash lines; and

Fig. 412 is arear elevationofthe cushioningand retarding mechanismwith parts vofwFig. 1 1 omit Referring vto the accompanying ,drawings and particularly to Figs. l and .2, the numeral Il designates the breechcasing of anautomatic firearm suitably secured to `a trunnion block', i2

through whichg barrel I3 is mounted and-connected atits breech or rear end tolabarrelfextension i4 mounted within thebreechcasing Il for longitudinal reciprocating movement tl1erein. The numeral` llidesignates the cover oi .a feed box mounted ontop ,of the casing l'l.and supportinga feed lever i6 .which `controls feeding of the cartridges lsuccessively into .thegun .silbstantially as disclosed in said Patent No.vvl,293,021.

The rear of the casing .l l lis closed by a remov'.

able back plate Il having-handles Iiltobem'anun ally graspedwhen removing or .applyingtheback plate for access tothe interior of the casing and said patent is cushioned and limited by a piston supported by a guide F, vcommonly known as a lock'irame.. In PatentNo.'1',628,226, the accelf `erator is illustrated,` but the rearward movement ofthe barrel extension'is cushioned vand limited by 'an'oil buiers shown in Fig. 2710i said patent.

The parts hereinabove ,identiii'ed' in connection with thepresent drawings and said Patents Nos, '1,293,021 and 1,628,226, have constituted standard equipment' on automatic firearms prior" to the present invention, andthe parts hereinabove videntiiied in connection with the said patents and especially the lock frames andaccelerators .were

especially provided to 'speed up or increase the rate of firing ofthe firearms. Y

According to my present invention, the accelerator is purposely dispensed with and mechaf nisin about tobe described especiallyv provided to slow down or retard the rate offiring ofthe automatic firearm. To `this end, in connection'with Figs. .f1-9 inclusive, Ifhaveshown one preferred form of the'invention, which I have .foundin actual practice, materially reducesthe rate o locl:'3l is moved downwardthe breechboltis free `to reciprocably move independently of thebarrel extension.I During the. forward movement of the barrel extension .from the position shown in 2, the lock -30 is movedupward andoperable during reciprocating movements of the partsby engagement with the camplate 3! secured to the bottom of 'the breech casing H, as disclosed in said foregoing patents, to lock thev breech bolt the mechanism contained therein. 'The back plate may be 0f any ,desired construction and secured to the' casing by any suitable meansso far as the present invention is concerned, but the `one `illustrated in the ,accompanying e, drawings -is made substantially in accordance with the .back y v vplate illustrate-:l in Patent No. v1,628,226 and includes as a part'thereof acushioning member. .I9 for the breech bolt 20 .which is mounted in the casing AVfor reciprocating movement, above the barrelextension. i4 and thelock frameor similar cushioning device 2i for the barrel extension f4,

and barrel extension together and maintainthem `locked when they are established in batteryl posi,-

tion. A trigger `bar 30 is pivotally supported 'on a pin 3i 'supported between the plates 25 andi] ,with its `rear end located for engagementby .the trigger 32 to actuate the firing mechanism.`

A vertically movable barrelfextension retarding member is mounted` betweenthe plates o'r sides 26. and 21 of thezlock frame and ,includesa .forwardly projecting..arm..33 having cuits-for.-

ward end a hook 34 locatedat thebottom ofthe lock frameand in alignment with the barrel ex.- tensiOn. The plates 26 and 21 are provided with vertical grooves and the retarding member has lateral tongues 36 slidably mounted in the grooves 35. At its top the retarding member is provided with a cam formation 39 engageable by a depending portion 40 on the rear end of the breech bolt to depress the retarding member when the breech bolt has nearly completed its course of travel to breech-closing position on counter-recoil movement. It will be noted that the retarding member is located at the forward end of the lock frame while the releasing member 40 on the breech bolt is located at the rear end of the breech bolt so that the breech bolt must travel substantially a distance equal to its entire length before the retarding member which engages with the barrel extension, as presently described, is released,Y A spring-'pressed plunger is located longitudinally in the lock frame between the cam member 39 and the arm 33 of the retarding member. A housing 4| is preferably formed as a part of a spacer block 42 located between and connecting the plates or sides 26 and 21 of the lock frame and through which the pivot 3| of the trigger bar 3D extends. A coil spring 43 is mounted on a rod 44, the rear end of which is slidable in the housing 4I. A tube or sleeve 45 surrounds the forward end of the spring and is movable through an opening 46 in the vertically movable barrel extension retarding member. The forward end of the rod 44 is provided with an enlarged head 41 having a slot 48 or other suitable means to facilitate removal of the rod. In the present construction, the head 41 has screw-threaded engagement with the sleeve `45 so that the spring 43 is partly compressed between the housing 4| and the shoulder of the enlarged end 41 of the rod 44. The rear of the barrel extension has a projection 5B aligned with the end 41 of the spring-pressed plunger or rod 44 when the parts are in assembled relation within the breech casing.

My invention provides for any suitable means for effecting movement of the hook 34 upwardly to engage the skirt 5| on the lower portion of whereby the skirt 5l on the rear of the barrel extension will engage with the beveled surface 52 on the hook 34 and cam the retarding member down when the breech bolt is forced rearwardly in the casing during functioning of the firearm.

An alternative form of means for resiliently forcing the retarding member upwardly is shown in Figs. 8 and 9 wherein the coil springs 54, previously mentioned, are housed in cups slidably mounted in openings 6| in the bottom of a part of the lock frame adjacent the forward end thereof.

I deem it important to provide for centering the means normally urging the retarding member upwardly so as to have even and smooth operation Y ofthe gun, that is,-to avoid applying pressure on the rear end of the barrel extension. It may be seen by reference to Figs, 1 3, that the forward end of the ho-ok 34 on the arm 33 of the retarding member engageable with the barrel extension is provided with a beveled surface 52 on its forward end which serves as a cam for contact by the skirt 5l on the barrel extension to move the retarding member down as the barrel extension moves from the position of Fig. 1 to the position of Fig. 2. In this connection, it is important to provide means for raising the retarding member after the skirt 5l has passed the hook 3-4 in its rearward travel, and I prefer, though it is not absolutely essential, to use resilient means such as a flat spring 53 in Figs. 1-7 inclusive, or coil springs 54 as shown in Figs. 8 and 9 to exert upward pressure on the arm 33cf the retarding member.

In the embodiment of the invention, shown in Figs. 1-'1 inclusive, the flat or leaf spring 53 is relatively wide at its rear end, as indicated by the numeral 56 in Fig. 4 to fit within grooves 51 in the rear portion of the side plates 26 and 21, so that the spring may be readily inserted into the position shown in the drawings with its narrower portion 58 extending forwardly along and beneath the lock frame and with its forward end bearing upwardly against the arm 33 of the retarding member so that the retarding member is .normallyheld in the position of Figs. 2 and 3,

the movable parts at either side of the center in excess of pressure at the other side of the center. Therefore, the flat spring 53 of Figs. 1-7 inclusive, is located with its longitudinal axis substantially in alignment with the longitudinal axis of the arm 33 of the retarding member; and in the construction of Figs. 8 and 9, the coil springs 54 are located at corresponding or equidistant points at opposite sides of the lock frame 'and retarding member,

Stabilized or guided movement of the springpressed plunger or rod 44 is obtained by providing longitudinal grooves 62 in the forward inner surfaces of the side plates 26 and 21, of the lock frame and further providing a plate 63 having lateral ribs or tongues 64 respectively and slidably located in the grooves 62. Preferably, the plate 63 has formed as an integral part thereof the tube 45 vwhich surrounds or houses the forward end of the plunger spring 43.

'Ihe lock frame is removably held in the casing by a spring-pressed plunger 65 housed within a tube 66 located between the rear portion of the plates 26 and 21, the projecting end of the plunger 65 being engageable in an opening suitably provided in the Vside of the breech casing.

To further stabilize the parts of the gun dur ing functioning thereof, especially the lock frame, I have provided on the exterior or outer sides of each of the plates 2G and 21 laterally extending studs 61 and 68 engageable in slots 68 respectively provided therefor in opposite sides of the breech casing, as shown in Figs. 1 and 2. By

`providing the pairs of studs 61 and 68 in spaced relation to each other on each side of the lock frame, I positively prevent vertical rocking movement of the lock frame during functioning of the gun. Of course, the slots or grooves into which the studs 61-68 fit are proportion to provide a close nt yet permitting easy removal and insertion of the lock frame.

As hereinbefore mentioned, the invention contemplates the provision of two forms of retarding and cushioning means for the breech bolt useable either jointly or separately, and whereas in Figs. l9 inclusive, I have shown and described a new ferm of cushioning and retarding means for barrel extensions; in Figs. 10-12 inclusive I have shown the said retarding means in combination with breech bolt retarding means, the two forms combined on a lock frame. Before proceeding with a detailed description of the structure illustrated in Figs. 10-12, I desire to make it clear that the second form of the inven tion shown in Figs. 10-12 may be used without the first form of Figs. 1-9 inclusive. 1 Referring to Figs. 10-12 inclusive, the numeral l designates the lock frame, as-inrigs. 1 9, and

having the'oppositely disposed forwardly extend ing arms 28 which engage the breech'bolt lock to unlock the breech bolt andbarrelextension upon explosion or firing vof each cartridge to permit independent relative movement of the breech bolt and barrel extension to the rear of the breech casing upon recoil. Also, as in Figs. 1-9, the numeral 30 designates the trigger bar pivotally supported on pin 3l mounted between the side plates-of the lock frame. Numeral `33 designates the vertically movable `hook-like barrel exten sion retarding member mounted andoperable in the same manner as disclosed in Figs. 1-9 inclusive. The member 33 is raisedv by `the spring 53 when the parts are in the position of Fig. 2 so that upon counter-recoil'rnovement of lthe barrel extension the hook 34 ofthe hooklil e member 33 will engage the skirt 5I depending from -the rear ofthe `barrel extension, as'shown in Fig. 3. Also, as in Figs. l-9 inclusive, a houslng 4I is formed as a part of the spacer block 42 within which-the rear of the rod supporting coil spring 43 is slidably mounted, and the forward end ofthe rod is provided with enlarged head 4l having screw-threaded .engagement in the sleeve 45 into which the forward end of the spring 43 extends to abut at its forward end the enlarged end or head of the rod 44. These parts operate in the same manner as described in connection with Figs. 1-9 inclusive.

While the foregoing arrangement issuiicient to very materially reduce the rate of firing of automatic firearms, the rate` of ring'may be-further reduced or the action of the gun slowed lup byproviding additional retarding and cushioning means on the lock frame cooperating with the breech bolt `during its reciprocating movements upon recoil and counter-recoil. To this end,

l as shown in Figs. 10-12inclusive, I provide a hook shown in Fig. 10, A coil spring '(1 is compressed between the lower side wall of the shoe and the hook I9 tending to normally urge or retain the hook in raised position for engagement with the depending portion 49 at the rear of the breech bolt when the breech bolt is in its rearmostposition. The front of the hook lI8 has a beveled surface 78 which is engaged by the beveled surface l19 of the breech bolt as it'moves rearward upon recoil to cam the hook down against the action o'f the spring 1l. As the breech bolt returns forward upon counter-recoil the hook engages the flange 40 on the breech'bolt to retard its forward movement. The retarding mechanism includes a retarder device, now to be described comprising a bracket r8l) which is rigidly secured to the lock frame adjacent the bottom thereof and preff erabiy against the spacer 42 and is provided with a bore 8| within which a rod 82 is slidably mounted for reciprocating movement. A Vcoil spring 83 is compressed between the vbracket 80 and the end of a rack 84 formed as a part of or `rigidly connected to the rod 82. The upper or vrear 'end 85 of the rack 84 is reduced and mounted in an opening in the forward end of the shoe 'i2 and preferably rigidly connected therein by any suitable means. A pinion 86 is pivoted to -theri'ght side of the lock frame as indicated at 81 and'hastwo sets of teeth, 'a relatively small peripheral group 88 which mesh with the teeth 89 on the yrack 84 and a larger group ofteeth 89' which cooperate with a. rocking pawl 9D pivoted to the left side of the lock frame adjacent the bottom thereof at 9|. The rocking pawl has claws or teeth 92 which alternately engag the larger teeth on the pinion.

In operation, the structure of Fig. `l1 functions as follows: as the breech bolt returns from its rearmost recoil position vtoward breech-closing or firing position, the pressure of the driving or counter-recoil spring which bears against the back plate and the breech bolt causes the depending portion 40 ofthe breech bolt vto move toward the hook l0. The screw 13 on which the rear endof the hook l0 is mounted moves downwardly' Yand forwardly-in the inclinedslot 14 underthe pressure exerted'on the hook 'l0 by the depending portion 4U of the breech bolt under the force of the driving or recoil spring, and consequently the hook i0 is moved in similar manner `until it has been disengaged from the depending portion 49 of the breech bolt. The shoe 12 also has movement in a direction extending forwardly and downwardly causing the rack 89 to be moved against the spring 83 partly compressing the spring. The extension'82 of the lrack: has guided movement in the bore 8| of the bracket 80 during the foregoing movements of the parts. The downward andforward'movement of the rack effects rotation of the pinion 86 by engagement of the teeth 88 of th'e pinion with the teeth 89 of the rack, and the rotation of the pinion causes alternate engagement of the claws on teeth 92 on the rocking pawl 90 with the teeth 89 on the pinion. Thus, the counter-recoil movement of the breech bolt is retarded by the rack and pinion or escapement mechanism above described and the operation of the hook and shoe. The compression of the spring 83 is gradual so that the movements of the rack and pinion and rocking pawl must also be gradual whereby the hook is not suddenly released from engagement with the breech bolt and the breech bolt is released only at a predetermined time.

As has been previously explained in connection with Figs. 1-9 inclusive, the hook-34 on the barrel extension retarding member 33 by engagement with the depending portion 5| on the rear of the barrel extension delays return of the parts to battery position. Thus by delaying the breech bolt by the hook 10 before it can begin its forward travel to engage the cam formation 39 on top of the barrel extension retarding member, the action or rate of firing of the gun is reduced.

As soon as the depending portion 40 on the rear of the breech bolt has passed, in its counterrecoil movement, the hook 10 in its completely depressedposition, the hook together with the shoe. rack, pinion and rocking pawl, are returned to the position shown in Fig. 11 with ythe hook 10 disposed in the path of movement of the beveled surface 19 on the rear of the depending por'- tion 40 of the breech bolt so that upon recoil the breech bolt will be again retarded or detained upon counter-recoil movement by engagement of the hook therewith, as shown in Fig. 11, and this according to the rate of firing desired to be had.

What I claim is:

1. An automatic firearm comprising in operative relationship a breech casing, a breech bolt mounted within said casing for automatic movement longitudinally thereof between ring and recoil positions in accordance with the functioning of the rearm, said breech bolt having adjacent its rearward end a projection depending from its underside, biasing means normally urging said breech bolt toward tiring position, and a lock frame mounted within said breech casing adjacent its rearward end, said lock frame being below said breech bolt, in combination with a retarder device mounted within said lock frame, and means for connecting said retarder device with said breech bolt, said connecting means being mounted substantially entirely within said lock frame and reciprocably movable in a path extending forward and downward in said lock frame and including a member normally projecting above said lock frame in position to engage said projection depending from said breach bolt during a portion of the movement of said breech bolt toward firing position, whereby said member connects said breech bolt to said retarder device during said portion of the movement of said breech bolt and the force of said retarder device opposes the force of said biasing means and causes a delay in the return of the breech bolt to ring position until said member moves downward in said lock frame suiiiciently to disengage said projection on said breech bolt.

2. An automatic iirearm comprising in operative relationship a breech casing, a breech bolt mounted within said casing for automatic movement longitudinally thereof between firing and recoil positions in accordance with the functioning of the rea1m,said breech bolt having adjacent its rearward end a projection depending from its underside, biasing means normally urg ing said breech bolt toward firing position, and a lock frame mounted within said breech casing adjacent its rearward end, said lock frame being below said breech bolt, in combination with a retarder device mounted within said look frame and comprising an escapement mechanism and operating pinion, and means for connecting said retarder device with said breech bolt, said connecting means being mounted substantially entirely within said lock frame and reciprocably movable in a path extending forward and downward in said lock frame and including a rack engageable with said pinion and a member normally projecting above said lock frame in position to engage said projection depending from said breech bolt during a portion of the movement of said breech bolt toward firing position, whereby said member connects said breech bolt to said escapement mechanism during said portion of the movement of said breech bolt and' said escapement mechanism opposes the force of said biasing means and causes a delay in the return of thebreech bolt to firing position until said member moves downward in said lock frame suiciently to disengage said projection on said breech bolt.

GEORGE IRONSIDE. 

